This invention relates to cleaning sand and other casting debris from the interior passageways formed in a sand cast, metal casting. Cast metal parts are commonly made by pouring molten metal into cavities formed in sand molds. Upon solidification of the metal, the sand mold is broken and the sand is separated from the metal part. Frequently, sand particles and other casting debris are lodged upon or adhered to the surfaces of the metal part. This material is removed through various cleaning techniques.
In casting a part which has interior passageways or hollow portions, it is common to use a core which may be made of sand and a suitable adhesive or resin, baked or otherwise solidified to form an obstacle around which the molten metal is cast within the sand mold cavity. After the metal is solidified, the interior core is broken out or otherwise removed, leaving the passageways or hollow portions within the casting. The removal of sand particles or other casting debris from the interior of the cast part, that is, from within the interior cavities or passageways is somewhat difficult and takes considerable time, depending upon the nature and shape of the part.
By way of example, cast internal combustion engine parts, such as the engine head or the engine block, are formed with numerous internal passageways which are difficult to clean following the casting of the metal. In high production foundries, the amount of time and material required for cleaning a casting, particularly the interior passageways and cavities within the casting, is important and, therefore, efforts have been made to clean such parts rapidly and effectively in order to reduce the expense of manufacturing the part.
An example of equipment developed for cleaning castings is disclosed in my prior U.S. Pat. No. 4,639,968, issued Feb. 3, 1987 to McKibben, Gould, Groh and Wuepper, for a Machine for Cleaning Castings. This patent illustrates a wheel, which rotates about a horizontal axis, upon which castings are mounted for movement through a number of cleaning stations. Alternating high pressure and low pressure blasts of air are applied to openings in the castings in opposite directions so as to loosen and blow out adhered sand or other debris. But, that equipment, and other available cleaning equipment are not always able to remove adhered sand and other debris from some relative long or curved interior spaces or of passageways formed within some cast metal parts. In the case of some cast engine parts, particularly engine heads and manifold parts having long and multiply curved internal passageways, there has been a need for a faster acting mechanism and method for better cleaning such castings in high production facilities.
Consequently, the invention herein concerns an improved method and apparatus cleaning the interior passageways of a castpart involving repetitive, alternating cycles of first, vibrating the entire casting and, second, applying an extremely short duration, high pressure air blast into the passageways.